Most present day passenger car motor vehicles have fuel tanks with filler pipes that contain an insert with an opening only big enough to permit passage therethrough of an unleaded fuel nozzle, with a venting or non-venting cap to sealably close the top of the pipe. A spring-closed flap door normally closes the fuel opening, and generally is of the non-sealing type that merely restricts the flow of leaded fuel by causing a splash-back of the fuel in the event a leaded fuel nozzle is attempted to be inserted.
The disadvantages of the present systems are that if the vehicle operator forgets to replace the cap after refueling, or if the cap is damaged or otherwise loose, the fill pipe is essentially open. This can effect the unwanted discharge of liquid fuel and fuel vapors and pollution of the atmosphere. Without some sort of device, such as, for example, a warning light on the dashboard of the vehicle, the operator would not be aware that the cap is not in place.
This invention is directed to a unitary module that is fixed in place in the fill pipe that, per se, contains all the elements for sealably controlling the flow of liquid/fuel vapors and venting through the fill pipe regardless of whether the closure cap is in place or not. The module, therefore, is a self- containment unit in that it allows all of the functions of filling and venting of the fuel as well as controlling the tank pressures and vacuum conditions.